This invention relates to a bellows of the type set out in U.K. patent application No. 2,113,123. Whilst the cover and the arms of this known bellows have a common continuous outer layer made from fabric, the inner layer which is provided for stiffening purposes consists of three individual parts formed by perforated sheets which are perforated along the edges of the pleats.
FIG. 1 represents the prior art and shows the conventional construction of the inner layer in a schematic view. The inner layer of a bellows of the whole bellows consists of an inner layer 1 for the cover of the bellows and two inner layers 2 for the two arms of the bellows. The inner layers 1 and 2 of the cover and the arms are cut in a triangular shape on the sides facing one another, so that the apexes 1a and 2a lie against one another but are not continuous. The inner layers 1 and 2 of the cover and the arms of the bellows are provided with perforations 3 in the region of the later edges of the pleats.
The inner layers 1 and 2 of the cover and the two arms of the bellows are adhered to a continuous outer layer made from fabric, and this ensures that the three inner stiffening layers hold together. Then the two arms of the bellows are folded in and, if required, crosspieces can also be fixed between individual pleats for further stiffening.
The main disadvantage of this known bellows according to FIG. 1 is that the apexes 1a, 2a of the inner layer of the cover and the arms pierce the outer fabric layer and damage this outer layer even after the bellows has been operating only for a comparatively short time.
The object of the invention, therefore, is to provide a bellows which is distinguished by a very stable and lasting construction.
In the bellows according to the invention the cover projects like a roof over the two arms and the apexes of the inner layer of the arms are supported on the inner layer of the cover, and therefore the grave danger of damage to the outer layer caused by the apexes of the inner layer of the arms, as occurs with the known bellows (FIG. 1), is avoided. Because of the particularly lasting and wear-resistant construction of these very critical parts of the bellows the construction according to the invention is distiguished by a long operating life.
The construction of the bellows according to the invention is advantageous above all for applications in which lasting sealing of the bellows is required.
Advantageous embodiments of the invention are the subject matter of the subordinate claims and are explained in connection with the description of two embodiments which are illustrated in the drawings.